As part of my new patio project (need to update that thread) I want a gas fire pit. I've seen some really nice concrete ones but they cost approx $2500 / 3000 for something I like. We have a machine / sheet-metal shop so I thought I could make a mold from steel, pour the concrete, then have the top surface polished. It will be 45" dia with a 32" inner bowl for a 30" high cap burner that can produce 300,000 btu, it will be manual ignition.The height is 24". Here is the burner I plan on using.
http://www.ebay.com/itm/30-SS-FIRE-PIT- ... 589438180f.
The mold will bolt together and is made from 10 ga steel, it takes 2ea) 48" x 120" sheets to produce the pieces in the laser, they will then be formed to the cone shape, have some parts welded on, then bolt to create the female form. The mold is designed, just waiting for the time to cut it.This will be able to be used multiple times if it works. I plan on having glass / ??? poured into the top of the mold so when it is polished there will be a color in the surface. The outside could be polished or some other finish, still debating. I'm not sure if this will need reinforcement (re-bar) or maybe fiber of some kind, also what size aggregate I should use. Anyone who knows about concrete could give me some info if possible.